Main class for jar file missing for Gradle task

Question

I have been trying to execute a jar file ssr.runner, jar using task with type JavaExec . But gradle is giving me the error that no main class specified . I am new to gradle so if any one could please elaborate in detail that would be great. Here is the task that I wrote:

task executeSqlScriptRunnerBeforeTenantCreation(type:JavaExec) {
    description "Execute ssr.runner to install certificates into the device"
    doLast {
        if(scriptRunnerVariables.get('SSR_INTERSECT_MOCK') == 'true') {

            println "Executing SQL Script Runner..."
            println "Adding certificates for mocked intersect service"

            if(scriptRunnerVariables.get('SSR_DB_TYPE') == 'SQL_SERVER') {
                classpath =  file("{$workingDir}\\ssr.runner.jar")
                main =  '-jar' 
                args '-dbtype', "${scriptRunnerVariables.get('SSR_DB_TYPE')}", '-dbhost', "${scriptRunnerVariables.get('SSR_DB_HOST')}", '-dbinstance', 
                "${scriptRunnerVariables.get('SSR_DB_INSTANCE')}", '-dbname', "${scriptRunnerVariables.get('SSR_DB_NAME')}", '-dbuser', "${scriptRunnerVariables.get('SSR_DB_USER')}",
                '-dbpass', "${scriptRunnerVariables.get('SSR_DB_PASS')}", '-sqlscriptpath', "${scriptRunnerVariables.get('SSR_INTERSECT_MOCK_DB_SCRIPT')}"  
            }    
        }
    }
}

Answer 1

First of all you're mixing two phases: execution and configuration . There's no need to add doLast for predefined tasks. See here . Then this is (probably) how the script should look like:

task executeSqlScriptRunnerBeforeTenantCreation(type:JavaExec) {
    description "Execute ssr.runner to install certificates into the device"

    if(scriptRunnerVariables.get('SSR_INTERSECT_MOCK') == 'true') {
        println "Configuring SQL Script Runner..."
        println "Adding certificates for mocked intersect service"

        if(scriptRunnerVariables.get('SSR_DB_TYPE') == 'SQL_SERVER') {
            main = '<FULLY QUALIFIED NAME OF CLASS YOU NEED TO RUN>' 
            classpath =  file("{$workingDir}\\ssr.runner.jar")            
            args '-dbtype', 
                 "${scriptRunnerVariables.get('SSR_DB_TYPE')}", 
                 '-dbhost', 
                 "${scriptRunnerVariables.get('SSR_DB_HOST')}", 
                 '-dbinstance', 
                 "${scriptRunnerVariables.get('SSR_DB_INSTANCE')}", 
                 '-dbname', 
                 "${scriptRunnerVariables.get('SSR_DB_NAME')}", 
                 '-dbuser', 
                 "${scriptRunnerVariables.get('SSR_DB_USER')}",
                 '-dbpass', 
                 "${scriptRunnerVariables.get('SSR_DB_PASS')}", 
                 '-sqlscriptpath', 
                 "${scriptRunnerVariables.get('SSR_INTERSECT_MOCK_DB_SCRIPT')}"  
            }
        }
    }
}

main was misconfigured there should be a fully qualified (with package) name of java class you need to run passed. Of course, what is configured via classpath , main , args and so on in configuration phase will be run in execution phase only if the two expressions in if block evaluate to true.